Multiple disc cartridge disc magazine

ABSTRACT

A recording/reproducing apparatus includes a plurality of toroidally arranged housing sections housing a plurality of disc cartridges in a stacked condition. Each housing section has apertures on its opposite lateral sides for taking out or housing the disc cartridges in the fore-and-aft direction parallel to the stacking direction of the disc cartridges. A lift mechanism supports and lifts the recording/reproducing units in the stacking direction of each of the recording/reproducing units. A transfer mechanism lifted by the lift mechanism along with the recording/reproducing units is adapted for taking out or housing the disc cartridges housed within the housing sections via one of the apertures of one of the housing sections facing each recording/reproducing unit.

This is a divisional of application Ser. No. 08/379,220, filed Jan. 27,1995, now U.S. Pat. No. 5,640,288.

BACKGROUND OF THE INVENTION

This invention relates to a recording and/or reproducing apparatushaving a disc exchange function. More particularly, it relates to arecording and/or reproducing apparatus in which plural disc cartridgesare housed within each of plural toroidally arranged housing sections,and in which desired ones of the disc cartridges are sequentiallyselected and taken out for recording and/or reproducing music signals onor from discs contained in the selected disc cartridges.

There has hitherto been employed a disc player apparatus in which pluraldisc cartridges are contained in a main member of the apparatus and inwhich desired ones of the disc cartridges are sequentially selected andloaded on a disc driving unit so that information signals, such as musicsignals, recorded on the discs housed within the disc cartridges, willbe reproduced continuously.

This type of the disc player apparatus has a cartridge housing sectionsfor housing plural disc cartridges and a cartridge transportingmechanism for selectively taking out a desired one of the disccartridges out of the cartridge housing sections for loading on a discdriving unit.

With the conventional disc player apparatus, having the disc exchangefunction, the cartridge housing sections are fixedly arranged within themain body of the apparatus. Consequently, for accommodating a largenumber of the disc cartridges, the cartridge housing sections need to beincreased in size, thus increasing the size of the apparatus. On theother hand, if a large number of the disc cartridges are housed withineach of the cartridge housing sections, the cartridge housing sectionsare increased in size. In addition, the disc cartridge transportingdistance from the cartridge housing sections to the disc driving unit isincreased, such that the cartridge transporting mechanism has to beincreased in size. As a result, it becomes difficult to reduce the sizeof the disc player apparatus.

OBJECTS AND SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide arecording and/or reproducing apparatus having the disc exchangefunction, in which a large number of the disc cartridges may beefficiently accommodated within a small housing space to render itpossible to reduce the size of the apparatus.

It is another object of the present invention to provide a recordingand/or reproducing apparatus having the disc exchange function, in whicha desired one of the disc cartridges may be correctly selected and thethus selected disc cartridge may be positively loaded on the discdriving unit.

It is yet another object of the present invention to provide a recordingand/or reproducing apparatus having the disc exchange function, in whichthe disc cartridges housed within the main member of the apparatus maybe exchanged easily.

The apparatus for recording and/or reproducing information signalsincludes a plurality of toroidally arranged housing sections eachhousing a plurality of recording media in a stacked condition. Eachhousing section has apertures on opposite lateral sides thereof fortaking out or housing the recording media in the fore-and-aft directionparallel to the stacking direction of the recording media. Therecording/reproducing apparatus also includes a plurality ofrecording/reproducing units arranged at a center position of thetoroidally arranged housing sections in a direction along the diameterof the toroid and facing each other on both sides of the center of thetoroid delimited by the plural housing sections, and a lift mechanismfor supporting each of the recording/reproducing units and lifting therecording/reproducing unit in the stacking direction of each of therecording/reproducing units. The recording/reproducing apparatus furtherincludes a transfer mechanism lifted by the lift mechanism along withthe recording/reproducing units and adapted for taking out or housingthe recording media housed within the housing units via one of theapertures of one of the housing sections facing eachrecording/reproducing unit, and a turntable carrying the toroidallyarranged housing units and adapted for selectively facing one of theplural housing sections to each of the recording/reproducing units. Therecording/reproducing apparatus also includes a rotating rivingmechanism for rotationally during the turntable about the center of thehousing section as a center of rotation. The turntable is rotatablymounted within the main member of the apparatus, in which there are alsomounted the rotating driving mechanism and the lift mechanism.

The main member of the apparatus includes a takeout/housing section inor from which the recording medium may be housed or taken out via theaperture of the housing section opposite to the aperture facing therecording/reproducing unit.

The housing sections are arranged on said turntable in a radialdirection from the center of a toroid defined by the housing sectionswith one of the apertures of each housing section being directed to thecenter of the center of the toroid and the other aperture of eachhousing section being directed outwardly from the center of the toroid.

Each of the plural housing sections or the turntable is provided with anengagement lug and the turntable or each of the plural housing sectionsis provided with an engagement recess and each of the housing sectionsis held on the turntable by interengagement of the engagement lug andthe engagement recess.

The main member of the apparatus has an entry/exit section via which thehousing section is taken out from the turntable out of the main memberof the apparatus.

The turntable has a plurality of engagement portions and a plurality ofgear portions provided between these engagement portions. The drivingmechanism has a mating engagement portion inter-engaged with theengagement portions of the turntable, a driving gear having a gearportion engaged with a mating gear portion on the turntable and adriving source for driving the driving gear. The gear portions of theturntable meshes with the gear portion of the driving gear forrotationally driving the turntable. The turntable is locked byinter-engagement of the engagement portions and the mating engagementportion so that at least one of the housing sections faces one of therecording/reproducing units.

The apparatus also includes first detection means for detecting therotational angle of the turntable and second detection means fordetecting the position of locking of the mating engagement portion ofthe driving gear with the engagement portion on the turntable. The firstdetection means has plural mating detection portions for detecting theposition of the engagement portions on the turntable and detectionportions for detecting the mating detection portions.

The lift mechanism has a plurality of driving gears rotationally drivenby a driving source and a plurality of engagement portions provided oneach of the driving gears for being engaged in engagement grooves formedin each of the recording/reproducing units. Each of the driving gears isrotationally driven by the driving source for lifting each of therecording/reproducing units along a guide.

The apparatus also includes, in addition to the first detection meansfor detecting the rotational angle of the turntable and the seconddetection means for detecting the position of locking of the matingengagement portion of the driving gear with the engagement portion onthe turntable, first position detection means provided on one end of amovement range of the recording/reproducing unit for detecting aninitial position of the recording/reproducing unit, and second positiondetection means for detecting the position of the recording/reproducingunit along the stacking direction.

The recording medium housed within the housing section may be a disccartridge containing a disc for recording information signals, such asan optical disc, or a disc itself.

With the present recording and/or reproducing apparatus, the turntableis rotated by a rotating driving mechanism for selectively directingplural housing sections arranged on the turntable to therecording/reproducing apparatus. The recording/reproducing unit facingthe selected housing section and the transfer mechanism for taking out adesired one of the plural disc cartridges housed in a stacked conditionin the housing section are directed to the desired disc cartridge in theselected housing section. The disc cartridge in the housing sectiondirected to the recording/reproducing unit is taken out of the housingsection by the transfer mechanism and loaded on therecording/reproducing unit for recording and/or reproducing informationsignals, such as music signals, on or from the disc housed within thedisc cartridge.

Other objects and advantages of the invention will become apparent fromthe following description of the preferred embodiments and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is perspective view showing a disc cartridge having housedtherein a magneto-optical disc for a recording and/or reproducingapparatus capable of re-recording information signals thereon, accordingto the present invention, when looking from its upper side.

FIG. 2 is a perspective view of the disc cartridge shown in FIG. 1, whenlooking from its lower side.

FIG. 3 is a perspective view showing a disc cartridge having housedtherein an optical disc for a recording and/or reproducing apparatuscapable only of reproducing information signals, according to thepresent invention, when looking from its upper side.

FIG. 4 is a perspective view showing the disc cartridge of FIG. 3, whenlooking from its lower side.

FIG. 5 is a perspective view showing a disc recording and/or reproducingapparatus according to the present invention.

FIG. 6 is a perspective view showing a magazine for a disc cartridgeconstituting the disc recording and/or reproducing apparatus accordingto the present invention.

FIG. 7 is a back side view showing a magazine for a disc cartridge.

FIG. 8 is a side view showing the state in which the disc cartridge isinserted into and detached from the magazine for the disc cartridge,with a portion of the magazine being broken away.

FIG. 9 is a plan view showing the state in which the disc cartridge isinserted into and detached from the magazine for the disc cartridge,with a portion of the magazine being broken away.

FIG. 10 is an enlarged schematic transverse cross-sectional view showingthe state of an engagement member when the disc cartridge is about to beinserted into the magazine for the disc cartridge.

FIG. 11 is an enlarged schematic transverse cross-sectional view showingthe state of the engagement member when the disc cartridge is beinginserted into the magazine for the disc cartridge.

FIG. 12 is an enlarged schematic transverse cross-sectional view showingthe state of the engagement member when the disc cartridge has beeninserted into the magazine for the disc cartridge.

FIG. 13 is a perspective view showing a turntable mechanism on which themagazine for the disc cartridge is mounted.

FIG. 14 is a front view of the turntable mechanism on which the magazinefor the disc cartridge is mounted, with a portion of the turntablemechanism being broken away.

FIG. 15 is a side view of the turntable mechanism on which the magazinefor the disc cartridge is mounted, with a portion of the turntablemechanism being broken away.

FIG. 16 is a plan view showing the turntable mechanism.

FIG. 17 is a plan view showing the state in which the magazine for thedisc cartridge has been loaded on the turntable mechanism.

FIG. 18 is a plan view showing a driving gear and a ring gear making upthe turntable mechanism.

FIG. 19 is a plan view showing the ring gear having been rotated through15°.

FIG. 20 is a plan view showing the ring gear having been rotated through22.5°.

FIG. 21 is a plan view showing the ring gear having been rotated through45°.

FIG. 22 is an exploded perspective view showing a disc driving unit ofthe disc recording and/or reproducing apparatus according to the presentinvention.

FIG. 23 is an exploded perspective view showing a recording/reproducingunit of the disc driving unit.

FIG. 24 is an exploded plan view showing a recording/reproducing unit ofthe disc driving unit.

FIG. 25 is a front view showing a recording/reproducing unit of the discdriving unit.

FIG. 26 is a front view showing the state in which a disc has beenloaded on the recording/reproducing unit of the disc driving unit.

FIG. 27 is a side view showing the recording/reproducing unit of thedisc driving unit.

FIG. 28 is a side view showing the state in which the disc has beenloaded on the recording/reproducing unit of the disc driving unit.

FIG. 29 is a plan view showing an arrangement of the disc driving unitand the magazine for the disc cartridge.

FIG. 30 is a plan view showing the state in which the disc cartridgewithin the housing section has been held by the disc cartridgetransporting mechanism provided within the disc driving unit.

FIG. 31 is a plan view showing the state in which the disc cartridgewithin the housing section is about to be held by the disc cartridgetransporting mechanism provided within the disc driving unit.

FIG. 32 is a plan view showing the driving unit of the disc cartridgemechanism.

FIG. 33 is a schematic front view showing the disc cartridgetransporting mechanism, with a portion thereof being broken away.

FIG. 34 is a schematic front view showing the disc cartridgetransporting mechanism.

FIG. 35 is a schematic front view showing the disc driving unit, with aportion thereof being broken away.

FIG. 36 is a side view showing the driving unit of the disc cartridgetransporting mechanism.

FIG. 37 is a schematic side view showing the disc cartridge transportingmechanism provided within the disc driving unit.

FIG. 38 is a side view showing the state in which the disc cartridge isbeing drawn out of the magazine for the disc cartridge by the disccartridge transporting mechanism.

FIG. 39 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing its initial state.

FIG. 40 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing the state in which each transportinggear has been rotated through 180°.

FIG. 41 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing the state in which each transportinggear has been rotated through 210°.

FIG. 42 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing the state in which each transportinggear has been rotated through 420°.

FIG. 43 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing the state in which each transportinggear has been rotated through 450°.

FIG. 44 is a side view of a driving unit for the disc cartridgetransporting mechanism, showing the state in which each transportinggear has been rotated through 760°.

FIG. 45 is a side view showing a gearing mechanism for verticallyactuating a recording/reproducing unit attachment plate.

FIG. 46 is a plan view showing a gearing mechanism for verticallyactuating a recording/reproducing unit attachment plate.

FIG. 47 is a side view showing a gearing mechanism for verticallyactuating a recording/reproducing unit attachment plate.

FIG. 48 is a perspective view showing an arrangement of a lift mechanismfor the disc recording and/or reproducing apparatus according to thepresent invention.

FIG. 49 is a front view showing the lift mechanism, with a portionthereof being broken away.

FIG. 50 is a plan view showing the lift mechanism, with a portionthereof being broken away.

FIG. 51 is a schematic front view of the lift mechanism, with a portionthereof being broken away.

FIG. 52 is a schematic plan view of the lift mechanism, with a portionthereof being broken away.

FIG. 53 is a side view showing the lift mechanism, with a portionthereof being broken away.

FIG. 54 is an enlarged schematic front view showing a position sensor ofthe lift mechanism.

FIG. 55 is an enlarged schematic front view showing the state in which alift block has been vertically moved by the lift mechanism.

FIG. 56 is a waveform diagram showing a detection signal detected by theposition sensor when the lift block is vertically moved by the liftmechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings, preferred embodiments of the presentinvention will be explained in detail.

The embodiment of the present invention, which is now to be described,is a disc recording and/or reproducing apparatus in which a disccartridge having housed therein a magneto-optical disc capable ofre-recording information signals, such as music signals, or disccartridge having housed therein an optical disc capable of onlyreproducing pre-recorded information signals, such as music signals, isused as a recording medium.

The disc cartridge having housed therein the magneto-optical disccapable of re-recording information signals, and the disc cartridgehaving housed therein the optical disc capable of only reproducingpre-recorded information signals, are now explained.

The magneto-optical disc capable of re-recording information signals,such as music signals, is comprised of a disc substrate of a transparentsynthetic resin, such as polycarbonate resin, about 64 mm in diameter,and a signal recording layer of a magnetic material deposited thereon.The signal recording layer is locally heated by a light beam outgoingfrom a light source and converged thereon by an objective lens to atemperature higher than the Curie temperature. The information signalsare recorded by application to the heated region of an external magneticfield modulated in accordance with the information signals to berecorded. The information signal thus recorded on the magneto-opticaldisc is read by radiating a linearly polarized light, such as a laserbeam, on the signal recording layer, and by detecting rotation in thedirection of polarization of the return light reflected by the signalrecording layer by photodetector means.

The replay-only optical disc, capable of reproducing only informationsignals, such as pre-recorded music signals, is formed by depositing areflective film of a metal material, such as aluminum, on a discsubstrate similar to the disc substrate of the magneto-optical disc.Recording of the information signals on the optical disc is by forming arow of micro-sized pits corresponding to the information signals by astamper at the time of fabrication of the disc substrate. Theinformation signals recorded on the replay-only optical disc are read byradiating a light beam on the row of pits and detecting the status ofthe return light from the optical disc by a photodetector.

A disc cartridge 320 having housed therein the magneto-optical disccapable of re-recording the information signals is configured as shownin FIGS. 1 and 2.

On the other hand, a disc cartridge 321 having housed therein thereplay-only optical disc is configured as shown in FIGS. 3 and 4.

The disc cartridge 320, having housed therein the magneto-optical disc,is comprised of a main cartridge member 305, fabricated by abutting andbonding an upper cartridge half and a lower cartridge half to eachother, and the magneto-optical disc housed therein. The main cartridgemember 305 of the disc cartridge 320 housing the magneto-optical disc isin the form of a square inscribed by the outer periphery of themagneto-optical disc. In the upper surface of the cartridge main member305 is formed a recording aperture 323 for exposing a portion of themagneto-optical disc housed therein to outside along the disc radius andfor intruding a magnetic head, not shown, into the inside of thecartridge main body 395, as shown in FIG. 11. In the lower surface ofthe cartridge main member 305 is formed a recording/reproducing aperture322 in registration with the recording/reproducing aperture 323 forexposing a portion of the magneto-optical disc housed therein to outsidealong the disc radius and for causing an optical pickup to face themagneto-optical disc, as shown in FIG. 2. In the lower surface of thecartridge main body 305 is formed a center aperture 313 in which isintruded a portion of a disc rotating driving mechanism for rotationallydriving the magneto-optical disc.

On the cartridge main body 305 housing the magneto-optical disc ismounted a shutter member 306 for opening and closing therecording/reproducing apertures 322 and 323. The shutter member 306 isformed by punching and bowing a thin metal plate material or molding asynthetic material in the cross-section shape of a letter U, and iscomprised of a pair of shutter plate portions large enough in size toclose the recording/reproducing apertures 322 and 323, and a connectingportion interconnecting the proximal ends of the shutter plate portions.The shutter member 306 has its connecting portion supported within aguide groove 307 formed in a lateral side of the cartridge main member305 so that the shutter member is movable between the position ofclosing the recording/reproducing apertures 322 and 323 and the positionof closing the recording/reproducing apertures 322 and 323.

The disc cartridge 320 is loaded on the cartridge loading unit of thedisc recording and/or reproducing apparatus, with the side thereofrunning at right angles to the lateral side of the cartridge main member305 supporting the shutter member 306 as an inserting side, with thedirection shown by arrow A in FIGS. 1 and 2 as the inserting direction.

On the other hand, the disc cartridge 321 housing the replay-onlyoptical disc has a cartridge main member 316 housing the optical disccoincident in outer size to the cartridge main member 305 housing themagneto-optical disc. The cartridge main member 316 is also fabricatedby abutting and bonding an upper cartridge half and a lower cartridgehalf together.

Meanwhile, since there is no necessity of employing a magnetic head forrecording information signals for the disc cartridge 321 housing thereplay-only optical disc, the upper surface of the cartridge main member316 remains solid without being formed with the aperture as shown inFIG. 3. The lower surface of the cartridge main member 316 is formedwith a reproducing aperture 322 for exposing a portion of the opticaldisc housed therein and for causing the optical pickup to face theoptical disc, as shown in FIG. 4. In the lower surface of the cartridgemain member 305 is formed a center aperture 313 in which is intruded aportion of a disc rotating driving mechanism for rotationally drivingthe optical disc.

On the cartridge main member 316 housing the magneto-optical disc, thereis also mounted a shutter member 317 for opening and closing therecording/reproducing aperture 322. The shutter member 317 is formed bypunching and bowing a thin metal plate material or molding a syntheticmaterial in the cross-section shape of a letter U, and is comprised of apair of shutter plate portions large enough in size to close only therecording/reproducing aperture 322, and a connecting portioninterconnecting the proximal ends of the shutter plate portions. Theshutter member 317 has its connecting portion supported within a guidegroove 307 formed in the lateral side of the cartridge main member 305so that the shutter member is movable between the position of closingthe recording/reproducing aperture 322 and the position of closing therecording/reproducing aperture 322.

The disc cartridge 321 is loaded on the cartridge loading unit of thedisc recording and/or reproducing apparatus, with the side thereofrunning at right angles to the lateral side of the cartridge main member317 supporting the shutter member 306 as an inserting side, with thedirection shown by arrow A in FIGS. 3 and 4 as the inserting direction.

At a mid portion of the connecting portion of each of the shuttermembers 306, 317 mounted on the disc cartridge 320 or 321, there isformed an engagement opening 308 engaged by a shutter closure member,not shown, adapted for displacing the shutter members 306, 317 towardsthe aperture closure position after the shutter members have been movedto the aperture opening position by the disc cartridges 320, 321 havingbeen loaded on the disc recording and/or reproducing apparatus.

The magneto-optical disc and the optical disc are each formed with acircular center aperture 304. The center aperture 304 is fitted with achuck plate 302 formed of a magnetic material, such as iron or stainlesssteel. The center aperture 304 and the chuck plate 302 are exposed tooutside via the center aperture 313 formed in each of the lower surfacesof the cartridge main members 305 and 316.

In the lower surfaces of the cartridge main members 305, 316 are formeda pair of positioning holes 309, 310 engaged by positioning pinsprovided on the recording/reproducing apparatus when the disc cartridges320, 321 are loaded on the recording/reproducing apparatus. Thesepositioning holes 309, 310 are formed so as to be located on both sidesof the recording/reproducing aperture 322, as shown in FIGS. 2 and 4.The positioning hole 309 is formed as an elongated opening having itslong axis lying along the inserting direction of the disc cartridges320, 321, while the positioning hole 310 is formed as a circular openingtightly engaged by the associated positioning pin.

In the lower surface of the lateral sides of the cartridge main members305, 316 opposite to the lateral sides thereof carrying the shuttermembers 306, 317 are formed a plurality of indicating holes 324 forindicating the types of the discs contained in the cartridge mainmembers 305, 316 and the state as to whether or not the informationsignals can be recorded on the discs. The disc cartridge 320 housing themagneto-optical disc capable of re-recording information signals isprovided with a mistaken recording inhibiting member. The mistakenrecording inhibiting member is arranged within the cartridge main memberso that it partially faces the indicating hole 324 and has its fingersupport 314 protruded via an opening 314a formed in the rear sideopposite to the front side or the inserting side of the cartridge mainmember 305. The mistaken recording inhibiting member opens or closes theindicating hole 324 by being moved by means of the finger support forindicating whether or not information signals may be re-recorded on themagneto-optical disc.

In portions of the lateral sides of the cartridge main members 305, 316close to the inserting sides thereof into the recording and/orreproducing apparatus are formed a pair of engagement recesses 312, 312engaged by portions of a cartridge entraining mechanism adapted forentraining the disc cartridges 320, 321 inserted into therecording/reproducing apparatus, as shown in FIGS. 2 and 4.

The cartridge main member 305 of the disc cartridge 320 housing themagneto-optical disc has a discrimination recess 311 for indicating thatthe disc contained therein is the magneto-optical disc. On the otherhand, the cartridge main member 316 of the disc cartridge 321 housingthe optical disc has a discrimination recess 318 for indicating that thedisc contained therein is the optical disc. These discriminationrecesses 311, 318 are respectively formed in the lower surfaces of thecartridge main members 305, 316 for being opened on the inserting sidesof the cartridge main members 305, 316, and are designed to indicate thedisc type by difference in depth.

The disc recording and/or reproducing apparatus according to the presentinvention is capable of housing a plurality of, e.g., 80, disccartridges 320, 321, and is adapted to select a desired one of thesedisc cartridges 320, 321 in order to permit information signals to berecorded on or reproduced from the magneto-optical disc or the opticaldisc housed within the selected disc cartridges 320, 321.

The disc recording and/or reproducing apparatus has a base 1,constituting the main member of the apparatus, as shown in FIG. 5. Thebase 1 is formed as a square casing and has a bottom surface at eachcorner of the lower surface of which is mounted a post 2 for installingthe apparatus in place. In the upper surface of the base 1 is formed acircular recess 4 delimited by a sidewall section 1a. The sidewallsection la delimiting the recess 4 has a cut-out 3 for partially openingthe recess 4 to outside. The recess 3 is formed at the position of thebase 1 facing the front side of the completed disc recording and/orreproducing apparatus.

Within the recess 4 is fixedly mounted a main chassis 13 via a bottomplate of the base 1. A support pillar 7 is set upright at a centerposition of the main chassis 13. A cover member 7 is mounted on theupper end of the support pillar 7 via a bearing member 6. The covermember 5 is rotatable about the support pillar 7 as indicated by arrow Cin FIG. 5. The cover member 5 is formed of transparent synthetic resinor glass and is formed as a bottomed cylinder having a circular topplate coextensive as the recess 4 and a peripheral wall depending fromthe periphery of the top plate.

The bearing member 6 is mounted at a center position of the top plate ofthe cover member 5 and supported for rotation about the support pillar7. Thus the cover member 5 is rotatable about the supporting pillar 7 asthe center of rotation. The cover member 5 is adapted for closing therecess 4 from the upper side by being mounted on the support pillar 7.

The peripheral wall of the cover member 5 is formed with an aperture 12.The cover member 5 is rotated about the support pillar 7 for facing theaperture 12 to the cut-out 3 for opening the recess 4 to outside of themain member of the apparatus. With the aperture 12 of the cover member 5thus facing the cutout 3, the disc cartridge 320 or 321 and a magazine11 for the disc cartridge as later explained may be introduced into ortaken out of the recess 4 via the cut-out 3. The cut-out 3 formed in themain member of the apparatus facing the aperture 12 formed in the covermember 5 serves as the entry/exit opening of the disc cartridge 320 or321 into and out of the magazine for the disc cartridge 11.

On a main chassis 13 set on the base 1 is rotatably mounted atoroidally-shaped turntable 15 constituting a turntable mechanism aslater explained. On the turntable 15 are removably arranged eightmagazines for the disc cartridges 11 so as to complete a toroidal shapeabout the center of the turntable 15 as the center. Each of thesemagazines 11 for the disc cartridges is adapted for housing ten disccartridges 320 or 321.

On the main chassis 13 are arranged a pair of disc driving units 8, 8making up a recording/reproducing unit of the recording/reproducingapparatus supported on the support pillar 7 via the lift mechanismserving as a transport mechanism as later explained. These disc drivingunits 8, 8 are lifted along the support pillar 7 by the lift mechanism,while the magazines for the disc cartridges 11 are rotated by theturntable mechanism for selecting a desired one of the disc cartridges320 or 321 from the magazine 11. The disc driving units 8, 8 extract theselected disc cartridge out of the magazine 11 and load the selecteddisc cartridge on the driving unit 8 for recording and/or reproducinginformation signals, such as music signals, on the disc housed withinthe disc cartridge 320 or 321. Each of the disc driving units 8 includesa disc rotating driving mechanism for rotating the disc, and an opticalhead as well as a magnetic head for recording and/or reproducinginformation signals on or from the disc.

The magazine for the disc cartridge 11, employed in the disc recordingand/or reproducing apparatus according to the present invention, is nowexplained.

The magazine for the disc cartridge 11 has a substantiallyparallelepipedic-shaped main magazine member 11a within which is defineda housing section 39 for stacking up a plurality of the disc cartridges320, 321 so that the major surfaces of the disc cartridges run parallelto one another. The housing section 39 is dimensioned to hold ten disccartridges 320 or 321 in a stacked-up position.

On the inner lateral surfaces of opposite side plates 11b and 11c of themain magazine member 11a defining the housing section 39 are formed aplurality of, herein ten, shelf-shaped protrusions 43, in plural tiers,as shown in FIG. 7. These protrusions 43 are formed horizontally fromthe front side towards the rear side of the main magazine member 11a.The protrusions are separated by an equal distance from one another. Thedisc cartridges 320 or 321, housed within the housing section 39, areinserted across a pair of opposing shelf-shaped protrusions 43, 43 sothat the disc cartridges are stacked in a horizontal position by havingboth lateral sides supported by the shelf-shaped protrusions 43.

The magazine main member 11a has its front and rear sides opened withthe rear-side opening serving as an entry/exit area of the disccartridges 320 or 321 into and out of the housing section 39. The disccartridges 320 or 321 are inserted into the housing section 39 via therear opening in the magazine main member 11a so as to be supportedacross the opposite shelf-shaped protrusions 43. The disc cartridge 320or 321 is inserted into the housing section 39 with the inserting frontside thereof into the recording/reproducing apparatus as the insertingside into the housing section 39. That is, the disc cartridge 320 or 321is inserted into the housing section 39 with the direction shown byarrow A in FIGS. 1 and 3 as the inserting direction. The disc cartridge320 or 321 thus housed within the housing section 39, is taken out viaapertures 11e, 11f formed in the front and rear sides of the magazinemain member 11a, respectively. That is, the disc cartridge 320 or 321,thus housed within the housing section 39, may be taken out from thefront side or the rear side of the magazine main member 11a, as desired.

On the rear side of the magazine main member 11a is mounted a stopmember 52 for preventing descent of the disc cartridge 320 or 321 housedwithin the housing section 39. The stop member 52 is formed as a rodhaving U-shaped pivots 52a at both ends. The stop member has its pivots52a pivotally mounted on the upper and lower surfaces of the magazinemain member 11a so that the stop member may be rotated between aposition facing the rear aperture of the magazine main member 11a and aposition receded from the rear aperture. When the stop member 52 hasbeen rotated to the position facing the aperture, it supports the rearend face of the disc cartridge 320 or 321 inserted into the housingsection 39 to inhibit descent of the disc cartridge from within thehousing section 39. When the stop member 52 has been rotated to theposition receded from the aperture, it opens the aperture in the rearsurface of the stop member 52 for enabling the disc cartridge 320 or 321to be introduced into or receded from the housing section 39.

On the front side of the magazine main member 11a having the aperture11e are formed plural engagement members 45 adapted for being engagedwith portions of the disc cartridges 320, 321 inserted into the housingsection 39, or for prohibiting these disc cartridges 320 or 321 frombeing disengaged from the housing section 39. Each of the engagementmembers 45 is provided in association with each disc cartridge 320 or321 supported across the shelf-shaped protrusions 43 facing each other.Specifically, the engagement members 45 are located on one side of theshelf-shaped protrusions 43 supporting the disc cartridges 320 or 321.

The engagement members 45 are housed within an engagement membercontaining section 47 provided on the outer lateral side of a side plate11b of the magazine main member 11a. These engagement members 45 aremounted in position by having engagement end portions 57 protruded intothe housing section 39 via ten cut-outs 44 formed in the side plate 11bof the magazine main member 11a in association with the shelf-shapedprotrusions 43 so as to be engaged with portions of the disc cartridges320 or 321 and by having proximal portions pivotally mounted on asupporting shaft 46 mounted for extending along the height of theengagement member housing section 47. The engagement members 45 arerotated about the supporting shaft 46 as the center of rotation forintruding or receding the engagement portions 57 into or out of thehousing section 39.

An auxiliary containing section 48 having the same configuration as thecontaining section 47 is mounted on the outer lateral surface of theopposite side plate 11c of the magazine main member 11a such that themagazine main member 11a is symmetrically shaped in the transversedirection. If necessary, the auxiliary containing section 48 may beprovided with plural engagement members 45 for prohibiting detachment ofthe disc cartridges 320 or 321 out of the housing section 39. Byproviding the engagement members 45 on both sides of the magazine mainmember 11a, the disc cartridges 320 or 321 housed within the housingsection 39 have both ends thereof held by the engagement members 45 forassuring positive housing of the disc cartridges within the housingsection 39.

Each engagement member 45 is thrust by a thrusting piece 50 which isformed by segmenting and bending an end portion of a spring plate member49 of a substantial width mounted in the containing section 47, so as tobe rotationally biased about the pivot 46 as the center of rotation inthe direction shown by arrow H in FIG. 9, that is in the direction inwhich the engagement portions 57 are protruded into the inside of thehousing section 39.

The spring plate member 49, having formed thereon plural end thrustingmembers 50 for thrusting the engagement member 45, has its connectingportion 49a to the proximal end of each thrusting piece 50 secured tothe rear wall of the containing section 47 by a set screw 55, with theend thrusting piece 50 protruded into the inside of the containingsection 47 via a slit 51 formed in the side wall portion of thecontaining section 47, as shown in FIG. 9. Each thrusting piece 50 hasits distal end engaged within the engagement recess 56 formed in thelateral surface of the engagement member 45 for rotationally biasing theengagement member 45 in the direction shown by arrow H in FIG. 9.

The engagement member 45, which has been rotationally biased in adirection shown by arrow H in FIG. 9 by the thrusting piece 50 protrudedvia the slit 51 into the containing section 47, has its retention lug 54at its proximal end retained by the inner wall of the containing section47, so that the engagement member has its rotational position limited inthe direction shown by arrow H in FIG. 9 at a position in which theengagement portion 57 is protruded a pre-set amount into the locus ofmovement of the disc cartridge 320 or 321 within the housing section 39.Thus, each engagement member 45 is thrust by the thrusting piece 50 andthereby has its engagement portion 57 protruded a pre-set distance intothe locus of movement of the disc cartridge 320 or 321 within thehousing section 39, so that, when the disc cartridge 320 or 321 isintroduced from the aperture 11f in the rear surface of the magazinemain member 11a into the inside of the housing section 39, an insertingside corner of the disc cartridge 320 or 321 is caused to bear on theengagement portion 57. When the engagement member 45 is at the initialposition of FIG. 10 in which the engagement member 45 has been thrust bythe thrusting piece 50, the end face of the engagement portion 57presents a surface 57a which is inclined in a direction of facing theinserting end of the disc cartridge 320 or 321 inserted via theinserting end of the disc cartridge 320 or 321 introduced via theaperture lie of the magazine main member 11a. When the disc cartridge320 or 321 is further introduced into the housing section 39, eachengagement member 45 has its inclined surface 57a thrust so that theengagement portion 57 is rotated in a direction of being receded out ofthe housing section 39 against the bias of the thrusting piece 50 asshown by arrow J in FIG. 11. When the disc cartridge 320 or 321 isfurther introduced as shown by arrow A in FIG. 11, the engagementportion 57 formed at the distal end of the engagement member 45 facesthe engagement recess 312 formed in the cartridge main member 305, 316.When the engagement portion 57 faces the engagement recess 312, therotational bias acting against the bias of the thrusting piece 57 isreduced to zero, so that the engagement member 45 is rotationally biasedin the direction shown by arrow H in FIG. 12 under the bias of thethrusting piece 50 and hence the engagement portion 57 is again engagedwith the engagement recess 312.

By the engagement portion 57 engaged in the engagement recess 312, thedisc cartridge 320 or 321 inserted into the housing section 39 iscontrolled in its movement towards the aperture 11e of the front surfaceof the magazine main member 11a so that the disc cartridge is held in acondition in which it is housed at a pre-set position in the housingsection 39. On the other hand, the engagement member 45 is rotated bythe disc driving unit 8 in a direction opposite to that shown by arrow Jin FIG. 12, against the bias of the thrusting piece 50, as laterexplained, for disengaging the engagement portion 57 out of theengagement recess 312 of the disc cartridge 320 or 321. The disccartridge 320 or 321, disengaged from the engagement member 45, may nowbe extracted via the front side aperture 11e of the magazine main member11a, as indicated by arrow K in FIG. 9.

The magazine for the disc cartridge 11 can accommodate ten disccartridges 320 or 321 in a stacked condition, as discussed previously.With the magazine for the disc cartridge 11, the disc cartridge 320 or321 can be inserted into or detached out of the housing section 39 viathe rear side aperture 11f of the magazine main member 11a.

The disc cartridge 320 or 321, thus housed within the housing section39, may be extracted out of the magazine main member 11a via the frontside aperture in the magazine main member 11a by rotating the engagementmember 45 in the direction of receding the end engagement portion 57 outof the housing section 39. Meanwhile, the engagement member 45 may berotated in a direction of being receded out of the housing section 39 asindicated by arrow J in FIG. 9, so that, when the disc cartridge 320 or321 is inserted via the front side aperture 11e of the magazine mainmember 11a, the engagement member 45 is thrust by the disc cartridges320 or 321 so as to be rotated against the bias of the thrusting piece50 in a direction in which the engagement portion 57 is receded out ofthe housing section 39. Thus the disc cartridge 320 or 321 may be housedwithin the housing section 39 via the front side aperture 11e in thefront side of the magazine main member 11a.

In a bottom surface lid of the magazine main member 11a delimiting thehousing section 39 of the magazine for the disc cartridge 11 is formedan engagement recess 40 extending from the front surface as far as a midportion on the rear surface of the casing 11a, as shown in FIG. 6. Theengagement recess 40 is employed for supporting the magazine 11 on theturntable 15 by fitting a fitting portion on a support member 36provided on the turntable 15 in the engagement recess.

If the disc cartridge 320 or 321 has been inserted in a mistaken mannerinto the magazine 11, that is if the disc cartridge has been insertedfrom a direction in which the engagement recess 312 formed on thecartridge main member 305, 316 is not in registration with theengagement portion 57 of the engagement member 45, the engagementportion 57 is not engaged with the engagement recess 312 but isprotruded via the front side aperture 11e in the magazine 11, thusallowing the user to recognize that the disc cartridge is being insertedfrom the mistaken direction.

The turntable 15, on which is mounted the above-described magazine forthe disc cartridge 11, is disc-shaped, and is supported for rotation atfour peripheral portions thereof by four supporting rolls 14 rotatablymounted via supporting shafts 35, set upright at respective corners of amain chassis 13, as shown in FIG. 13. The turntable 15 has its midportion formed with a circular aperture 34 the inner rim of which issupported by plural support rolls 33 rotatably mounted via supportingshafts 33a set upright on the main chassis 13. Thus the turntable 15 issupported on the main chassis 13 so as to be rotated by being guided bysupporting rolls 14, 33.

On the turntable 15 are mounted eight supporting members 36 at an equalinterval in the circumferential direction of the turntable 15, as shownin FIGS. 14 and 15. On the upper surface of each supporting member 36 isformed an engagement protrusion 38 engaged in the engagement recess 40formed in the magazine for the disc cartridge 11. The magazine for thedisc cartridge 11 is mounted on the turntable 15 by engaging theengagement protrusion 38 in the engagement recess 40. The engagementprotrusion 38 has engagement pins 37, 37 which may be emerged or recededand which are adapted for being engaged in engagement recesses in thebottom surface of the magazine for the disc cartridge 11 for positioningthe magazine 11 with respect to the supporting member 36.

For supporting the magazine for the disc cartridge 11 by the supportingmember 36, the magazine for the disc cartridge 11 is set on thesupporting member 36 so that the front side aperture 11e of the magazinemain member 11a is directed to the inner periphery of the turntable 15,and the engagement protrusion 38 is progressively engaged in theengagement recess 40. When the magazine for the disc cartridge 11 ismounted on the associated supporting member 36, the magazine for thedisc cartridge 11 is oriented so that the front side aperture 11e isdirected towards the inner periphery of the turntable 15 as shown inFIG. 15. In this manner, a number of the magazines 11 may be toroidallyarranged on the turntable 15, as shown in FIG. 17.

The turntable 15, having the magazines 11 mounted thereon by therespective supporting members 36, is rotationally driven by a drivingmotor 18 mounted on the main chassis 13. The driving motor 18 is mountedvia a motor attachment plate 17 set upright on the main chassis 13 so asto be protruded upwards via the circular aperture 34 in the turntable15, as shown in FIG. 13. A pair of such support plates 16, also servingas the lift mechanism as later explained, are mounted on the mainchassis 13 so as to be parallel to each other. Thus the motor attachmentplate 17 is set upright on one of the supporting plates 16.

The driving motor 18 is mounted on the motor attachment plate 17 so thatits driving shaft runs parallel to the major surface of the main chassis13. The distal end of the worm gear 19 carries a worm gear 19 meshingwith a worm wheel 20 rotatably mounted via a supporting shaft 21 setupright on the motor attachment plate 17. The worm wheel 20 has itsrotary shaft extending at right angles to the major surface of theturntable 15 and is formed with a first spur gear 23 via a coaxialcolumnar portion extending to the lower side. The first spur gear 23 isprotruded towards the lower side of the main chassis 13 via athrough-hole formed in the main chassis 13, as shown in FIG. 14.

On the lower surface of the main chassis 1 is formed a second spur gear24 via a rotary shaft 25 mounted near the first spur gear 23 towards thelateral edge of the main chassis 13. A timing belt 22 is mounted betweenthe first and second spur gears 23 and 24. When the driving motor 18 isrun in rotation, the second spur gear 24 is rotated via the worm gear20, the first spur gear 23 and the timing belt 22.

The rotary shaft 25 supporting the second spur gear 24 is passed throughthe main chassis 13 to reach the upper surface of the main chassis 13.On the upper end of the rotary shaft 25 is mounted a driving gear 26having its outer periphery formed with an engagement lug 27, as shown inFIG. 13. The end face of the engagement protrusion 27 is an arcuatesurface having a rotary shaft 25 as the center. The driving gear 26 hasa gear portion 26a in its portions other than the engagement lug 27.

On the lower surface of the turntable 15 is formed a ring gear 28coaxial as the turntable 15, as shown in FIGS. 13, 16 and 17. The ringgear 28 constitutes the follower gear meshing with the driving gear 26.On the outer peripheral surface of the ring gear 28 is formed a gearportion 28a meshing with the driving gear 26 and first to eighthengagement recesses 29a to 29h engaged with an engagement protrusion 27formed on the driving gear 26. These engagement recesses 29a to 29h areformed at an interval of 45° in the circumferential direction of thering gear 28. These engagement recesses 29a to 29h are formed on acurved surface having the same radius of curvature as the engagement lug27 provided on the driving gear 27. Thus, when the ring gear 28 isengaged with the driving gear 26, the engagement recesses 29a to 29hconstitute a portion of a circumference of a circle centered about thesupporting shaft 25 supporting the driving gear 26. In the initial stateshown in FIG. 18 in which the engagement lug 27 is engaged with thefirst engagement recess 29a, the engagement lug 27 is engaged with theengagement recesses 29a to 29h with its arcuate end face kept in contactwith the bowed bottom surface of the engagement recess 29a.

With the ring gear 28, the number of teeth formed between the first toeighth engagement recesses 29a to 29h is set so as to be equal to thenumber of teeth of the gear portion 26a of the driving gear 26. That is,when the driving gear 26 performs one complete revolution from theinitial state shown in FIG. 18 in which the engagement lug 27 providedon the driving gear 26 is engaged with the first engagement recess 29a,the ring gear 28 is rotated 45° in the direction shown by arrow F inFIGS. 19 to 21 so that the engagement lug 27 on the driving gear 26 isengaged in the second engagement recess 29b. Thus the ring gear 28 isrotated 45° each time the driving gear 26 performs one completerevolution for sequentially engaging the engagement lug 27 in the firstto eighth engagement recesses 29a to 29h.

When the engagement lug 27 on the driving gear 26 is engaged in one ofthe first to eighth engagement recesses 29a to 29h, the rotation of theturntable 15 is controlled unless the driving gear 26 is rotated by thedriving motor 18.

The turntable 15 is rotated in unison with the ring gear 28, by drivingrotation of the driving gear 26. By the engagement lug 27 of the drivinggear 26 with one of the first to eighth engagement recesses 29a to 29hformed in the ring gear 28, the magazine 11 placed in registration withthat one of the first to eighth engagement recesses 29a to 29h which isengaged with the engagement lug 27 is caused to face the disc drivingunit 8. Since the disc recording and/or reproducing apparatus of thepresent embodiment has a pair of disc driving units 8, two of themagazines for the disc cartridges 11 are caused to simultaneously facethe disc driving units 8, 8.

On the turntable 15 are provided first to eighth discriminationdetection units 31a to 31h, in association with the first to eighthengagement recesses 29a to 29h formed on the ring gear 28, fordiscriminating these first to eighth engagement recesses 29a to 29h.These first to eighth discrimination detection units 31a to 31h areprovided on the turntable 15 for facing the gear portions 28a of thering gear 28 associated with the first to eighth engagement recesses 29ato 29h, respectively. These first to eight discrimination detectionunits 31a to 31h are provided with comb-shaped discrimination detectionpieces 31i, as shown in FIG. 13. The number of the respectivediscrimination detection pieces 31i formed in the first to eighthdiscrimination detection units 31a to 31h differs from onediscrimination detection piece to another. Specifically, the numberincreases sequentially by one beginning from the first discriminationdetection pieces 31a, such that one discrimination detection piece 31iis formed in the first discrimination detection unit 31a and eightdiscrimination detection pieces 31i are formed in the eighthdiscrimination detection unit 31a. The first to eighth discriminationand detection units 31a to 31i are arranged so that the comb-shapeddiscrimination pieces 31i are located on the circumference of one andthe same circle centered about the center of rotation of the turntable15.

On the main chassis 13 is arranged a detection unit 32 constituted by aphotosensor, such as a photocoupler, for detecting the first to eighthdiscrimination detection units 31a to 31h rotated in unison with therotating turntable 15. The detection unit 32 is arranged on the locus ofrotational movement of the first to eighth discrimination detectionunits 31a to 31h for detecting and discriminating the first to eighthdiscrimination detection units 31a to 31h travelling on the detectionunit 32. The detection output of each of the first to eighthdiscrimination detection units 31a to 31h discriminated and detected bythe detection unit 32 is inputted to a driving control circuit, notshown, for controlling the driving of the apparatus in its entirety.

On the main chassis 13 is mounted a rotation detection sensor 30 in thevicinity of the driving gear 26 for detecting the rotational angularposition of the driving gear 26. The rotation detection sensor 30detects that the engagement lug 27 provided on the driving control gear26 is directed to the ring gear 28, that is the engagement lug 27 isengaged with one of the first to eighth engagement recesses 29a to 29hformed on the rig gear 28, and issues a detection output which isinputted to the driving control circuit.

The driving control circuit, to which detection outputs of the detectionunit 32 and the rotation detection sensor 30 are inputted, is capable ofdetermining, based on detection outputs of the detection unit 32 and therotation detection sensor 30, which of the magazines for the disccartridges 11 on the turntable is directed to the disc driving unit 8.

A number of engagement lugs 27, instead of one, may be provided on theouter periphery of the driving gear 26. In such case, gear porions 26aneed to be provided between neighboring engagement lugs 27.

The disc driving unit 8, on which the disc cartridge 320 or 321 housedwithin the magazines for the disc cartridge 11 mounted on the turntable15 is selectively loaded for recording/reproducing the informationsignals, such as music signals, on or from the magneto-optical disc orthe optical disc, housed within the disc cartridge 320 or 321, includesa housing 8a having a top plate 126, a bottom plate 58 and a pair ofside plates 123, 123 interconnecting opposing sides of the top plate 126and the bottom plate 58. A front plate 66 is formed upright on one endof the bottom plate 58 on the left front side of the housing 8a in FIG.22. The front plate 66 is formed with such a height defining a gap forinsertion of the disc cartridge 320 or 321 between it and the top plate126. This gap delimits an entry/exit opening for the disc cartridge 320or 321.

On the bottom plate 58 of the housing 8a is mounted for verticalmovement an attachment substrate 59 of the recording/reproducing unitsubstantially in the form of a flat plate. On the attachment substrate59 are mounted a disc table 60 for loading a disc housed within the disccartridge 320 or 321, cartridge positioning pins 63 and 64, andcartridge supporting pins 65, 65, as shown in FIGS. 23 to 28. Thecartridge positioning pins 63 and 64 and the cartridge supporting pins65, 65 are provided in registration with the corners of the lowersurface of the disc cartridge 320 or 321.

The disc table 60 is mounted on a driving shaft of a spindle motor 190mounted on the lower surface of the attachment substrate 59 forconstituting the disc rotating driving mechanism. The driving shaft ofthe spindle motor 190 is protruded from the upper surface of theattachment substrate 59 via a through-hole bored in the attachment plate59. The disc table 60 is substantially disc-shaped and is adapted forbeing intruded into the inside of the cartridge main member 305, 316 viaa center opening 313 formed in the disc cartridge 320 or 321 loaded onthe attachment plate 59. The disc table 60 has in its upper surface aprojection engaging in a center hole 304 of the disc and has mountedthereon a magnet, not shown, for attracting the chuck plate 302. Whenintruded into the inside of the cartridge main member 305 or 316 via thecenter opening 313 in the disc cartridge 320 or 321, the disc table 60supports the rim of the center hole 304 of the disc near its outer rim,while engaging the projection in the center hole 304. In addition, thedisc table attracts the chuck plate 302 by the magnet for positioningand holding the magneto-optical disc or the optical disc housed withinthe cartridge main member 305 or 316. The magneto-optical disc or theoptical disc thus loaded on the disc table 60 is rotated in unison withthe disc table 60 by rotational driving of the spindle motor 190.

The cartridge positioning pins 63, 64, set upright on the attachmentsubstrate 59, are conically shaped so as to be tapered towards thedistal ends. When the disc cartridge 320 or 321 is loaded on thecartridge loading unit on the attachment substrate 59, the cartridgepositioning pins 63, 64 are engaged in the positioning holes 310, 310formed in the lower surfaces of the cartridge main members 305, 316 forsetting the loading position of the disc cartridge 320 or 321. Thecartridge positioning pins 65, 65 are columnar-shaped with planar endfaces and are set on the attachment substrate 59. These cartridgesupporting pins 65, 65 support the corners of the lower surface of thedisc cartridge 320 or 321 loaded on the attachment substrate 59 forsetting the loading height position relative to the attachment substrate59.

On the lower surface of the recording/reproducing unit attachmentsubstrate 59 is mounted an optical pickup 61. The optical pickup 61includes a light source, such as a semiconductor laser, for radiating alight beam to the disc loaded on the disc table 60, an objective lensfor condensing the light beam outgoing from the disc for radiating thecondensed light on the disc, and a light receiving device, such as aphotodetector, for detecting the return light reflected from the discfor detecting the information signals recorded on the disc. The opticalpickup device 61 is movably supported on a shaft 188 arranged on thelower surface of the attachment substrate 59 and is guided by a pickupfeed unit, not shown, along the shaft 188 so as to be moved along theradius of the magneto-optical disc or the optical disc loaded on thedisc table 60. The optical pickup 61 causes the objective lens to facethe upper surface of the attachment substrate 59 via an aperture 62formed in the attachment substrate 59.

On the optical pickup 61, there is mounted, via a supporting arm 156, amagnetic head device 155 movable in unison with the optical pickup 61.The head supporting arm 156 is mounted via a rotary shaft 187 on thedistal end of an arm supporting plate 156a mounted on the optical pickup61 so that the distal end of the arm supporting plate is projected onthe upper surface of the attachment substrate 59. Since the head arm 156is mounted for being extended over the upper surface of the attachmentsubstrate 59, the magnetic head device 155 mounted at the distal end ofthe head arm via a gimbal spring faces the objective lens of the opticalpickup 61. By rotation of the head supporting arm 156 about the rotaryshaft 187 as the center of rotation, the magnetic head device 155 ismoved in a direction towards and away from the objective lens.

On the attachment substrate 59, the disc cartridge 320 or 321 is loadedin position with the aid of the cartridge positioning pins 63, 64 sothat the magneto-optical disc or the optical disc is loaded in positionon the disc table 60. When the disc cartridge 320 housing themagneto-optical disc capable of re-recording information signals isloaded on the attachment substrate 59, the objective lens of the opticalpickup 61 and the magnetic head device 155 approach and face each otherwith the magneto-optical disc in-between. If the recording/reproducingapparatus of the embodiment illustrated is set to the recording mode,the magnetic head device 155 is intruded via the recording/reproducingaperture 323 into the inside of the main cartridge member 305 for beingin sliding contact with the magneto-optical disc. On the other hand, ifthe disc cartridge 321 housing the replay-only optical disc is loaded onthe attachment substrate 59, the magnetic head device 155 is held at aposition spaced apart from the disc cartridge 321 so that only theoptical pickup 61 is caused to face the optical disc via therecording/reproducing aperture 322.

Consequently, with the present disc recording/reproducing apparatus,when the disc cartridge 320 housing the magneto-optical disc capable ofre-recording information signals is loaded on the attachment substrate59, information signals may be recorded on or reproduced from themagneto-optical disc. On the other hand, if the disc cartridge 321housing the replay-only optical disc is loaded on the attachmentsubstrate 59, simply the information signals, such as music signals,pre-recorded on the optical disc, may be reproduced.

On opposite lateral sides of the attachment substrate 59 areprotuberantly formed pairs of supporting pins 157, 158 and 159, 160, asshown in FIG. 23. These supporting pins 157, 158 and 159, 160 areintroduced into guide holes 161, 162 and 163, 164 bored in guide plates160, 160 formed upright on both opposite sides of a bottom plate 58 ofthe housing 8a. These guide holes are formed parallel to one anotheralong the height of the guide plates 160. The attachment substrate 59 ismovable vertically in a direction towards and away from the bottom plate58 by shifting the supporting pins 157 to 160 through these guide holes161 to 164.

A slide plate 167 is mounted between the bottom plate 58 and theattachment substrate 59. The slide plate 167 is formed on its oppositesides with a pair of side plates 168, 169. The slide plate 167 is formedwith slide guide holes 170, 171 and 186 in which are engaged slide guidepins 165, 166, 185 set upright on the bottom plate 58. The slide plate167 is arranged on the bottom plate 58 so as to be movable by beingguided by the slide guide pins 165, 166 and 185 within the range of theslide guide holes 170, 171 and 186. The slide plate 167 is arranged onthe bottom plate 58 by the side plates 168 and 169 being positionedbetween the attachment substrate 59 and the guide plates 160 and 160.The side plates 168 and 169 of the slide plate are formed with inclinedguide grooves 172, 173 and 174, 175 passed through by supporting pins157, 158 and 159, 160 provided on the attachment substrate 159. Theseinclined guide grooves 172, 173 and 174, 175 are gradually inclined fromthe forward ends towards the rear ends, as shown in FIG. 23, as shown inFIG. 23, so that, when the supporting pins 157, 158 and 159, 160 arepositioned at the forward and rear ends of the inclined guide grooves172, 173 and 174, 175, the attachment substrate 59 is located below thebottom plate 58 and raised above the bottom plate 58, respectively.

The slide plate 167 is biased to be moved towards the front sideindicated by arrow I in FIG. 23 by a tension spring 177 mounted betweena spring retainer 191 mounted on the front plate 66 and a springretention pin 176. A rack gear 178 is mounted at the rear end of theslide plate 167 for being protruded towards the rear of the bottom plate58.

On both sides of the attachment substrate 59 are arranged a pair ofmetal wires 67, 67 for extending on the bottom plate 58 in thefore-and-aft direction. The front sides of these wires 67, 67 areretained by retainers 68, 68 of the front plate 66 so as to be extendedhorizontally towards rear via the upper end of the front plate 66. Therear ends of the wires 67, 67 are retained by supporting pieces 72, 72depending at the rear side of the bottom plate 58. On the wires 67, 67is set the disc cartridge 320 or 321 inserted via the disc cartridgeinserting aperture. On the lower surface of the top plate 126 are formeda pair of guide rails 70, 70 for extending in the fore-and-aftdirection. The disc cartridge 320 or 321, set on the wires 67, 67, isclamped between the wires 67, 67 and the inner sides of the guide rails70, 70 and is movable only in the fore-and-aft direction by being guidedby the guide rails 70, 70, as shown in FIGS. 34 and 35.

When at a position displaced away from the bottom plate 58, theattachment substrate 59 carrying the recording/reproducing unit isintruded into a space between the wires 67 and 67 for positioning thecartridge positioning pins 63, 64 and the cartridge supporting pins 65,65 above the wires 67, 67. Thus, when the disc cartridge 320 or 321 issupported across the wires 67, 67, the disc cartridge 320 or 321 may bepositioned and loaded on the cartridge loading unit on the attachmentsubstrate 59, as a result of upward movement of the attachment substrate59, as shown in FIGS. 26 and 28. When the attachment substrate 59 ismoved towards the lower side of the bottom plate 58, the attachmentsubstrate 59 is receded from the space between the wires 67, 67 forretreating the disc table 60, the cartridge positioning pins 63, 64 andthe cartridge supporting pins 65, 65 to below the wires 67, 67.Consequently, the disc cartridge 320 or 321 set on the sires 67, 67 ismovable on the wires 67, 67 without being set on the attachmentsubstrate 59, as shown in FIGS. 25 and 27.

Meanwhile, the head supporting arm 156 and the magnetic head device 155are positioned above the disc cartridge 320 or 321 set on the wires 67,67 regardless of whether the attachment substrate 59 is at the upperposition or at the lower position.

On the bottom plate 58 is mounted a driving motor 80 for controlling thehorizontal transfer movement of the disc cartridge 320 or 321 and thevertical movement of the attachment substrate 59 carrying therecording/reproducing unit, as shown in FIGS. 23 and 24. On the drivingshaft of the driving motor 80 is mounted a driving gear 117 meshing witha first transmission gear 81 rotatably supported on the bottom plate 58.A second transmission gear 150 smaller in diameter than the firsttransmission gear 81 is coaxially and integrally mounted on the firsttransmission gear 81. The second transmission gear 150 meshes with athird transmission gear 82 rotatably supported on the bottom plate 58. Afourth transmission gear 151 smaller in diameter than the thirdtransmission gear 82 is coaxially and integrally mounted on the thirdtransmission gear 82. The fourth transmission gear 151 meshes with afifth transmission gear 83 mounted substantially centrally of a transferdriving shaft 84 rotatably mounted on the bottom plate 83. That is, whenthe driving motor 80 is driven in rotation, the transfer driving shaft84 is run in rotation. On both ends of the transfer driving shaft 84 aremounted a pair of transfer driving shafts 85, 85.

On both sides of the bottom plate 58 are arranged each one set of firstto third transfer gears 86, 88 and 90 making up a first recording mediumtransfer mechanism, as shown in FIGS. 22 and 32. The first to thirdtransfer gears 86, 88 and 90 of the sets, making up the recording mediumtransfer mechanism, are arranged symmetrically on both sides of thebottom plate 58 so as to be rotated in the same direction in a timedrelation to one another. The transfer gears 86, 88, 90 and 86, 88, 90 ofthe respective sets are rotatably supported via supporting shafts 118,120, 122 and 118, 120, 122 set upright on the opposite inner surfaces ofthe side plates 123, 123 of the housing 8a. These supporting shafts 118,120, 122 and 118, 120, 122 are set upright on the side plates 123, 123at the same height from the bottom plate 58 for extending along thelength of the side plates 123, 123. Consequently, the transfer gears 86,88, 90 and 86, 88, 90 of the respective sets, supported by thesesupporting shafts 118, 120, 122 and 118, 120, 122, are arranged in a rowalong the length of the side plates 123, 123.

The transfer driving gears 85, 85 mounted on both ends of the transferdriving shaft 84 mesh with the first transfer gears 86, 86 positioned atthe rearmost position of the housing 8a. Between the first transfergears 86, 86 and the second transfer gears 88, 88 are mounted reversinggears 87, 87 simultaneously meshing with these first transfer gears 86,86 and the second transfer gears 88, 88. These reversing gears 87, 87are rotatably supported by supporting shafts 119, 119 set on the sideplates 123, 123 of the housing 8a. Between the second transfer gears 88,88 and the third transfer gears 90, 90 are mounted reversing gears 89,89 simultaneously meshing with these second transfer gears 88, 88 andthe third transfer gears 90, 90. These reversing gears 89, 89 are alsorotatably supported by supporting shafts 121, 121 set on the side plates123, 123 of the housing 8a.

By the transfer driving gears 85, 85, mounted on both ends of thetransfer driving shaft 84 for rotation in unison with the transferdriving shaft 84, being driven in rotation, the first to third transfergears 86, 88, 90 and 86, 88, 90 of the respective sets, arranged on bothsides of the bottom plate 58, are rotated in the same direction in atimed relation to one another.

First to third engagement pins 91, 92 and 93 are mounted for beingprotruded towards the inner side of the housing 8a at positions offsetrelative to the center of rotation of the first to third transfer gears86, 88, 90 and 86, 88, 90 of the respective sets. These engagement pins91, 92 and 93 are set via a supporting plate 127 mounted insuperposition on the respective transfer gears 86, 88 and 90, as shownin FIGS. 22 and 36. These engagement pins 91 to 93 are each of athickness substantially equal to the interval between the engagementpins 86, 88, 90. The engagement pins 91 to 93 are protruded for facingthe ends of the gear portions formed on the outer peripheral surfaces ofthe transfer gears 86, 88, 90.

On the bottom plate 58 are arranged movable members 73, 73 for extendingalong the length of the gear train of the first to third transfer gears86, 88, 90 of the respective sets. These movable members 73, 73 are eachformed with through-holes 74, 74 through which are passed a pair ofmovement guide shafts 69, 69 arranged parallel to each other on bothsides of the bottom plate 58, and are supported for movement along thelength of the gear train of the first to third transfer gears 86, 88, 90of the respective sets by being guided by the movement guide shafts 69,69. The movable members 73, 73 are supported for movement by themovement guide shafts 69, 69 by movement guide pieces 76, 76 mountedupright on the upper ends of the movable members 73, 73 being engaged inengagement grooves 79, 79 formed in the guide rails 70, 70 forcontrolling the rotation about the movement guide shafts 69, 69.

On the outer sides of the movable members 73, 73 facing the first tothird transfer gears 86, 88 and 90 are formed engagement grooves 75engaged by the engagement pins 91, 92 and 93. The engagement groove 75is formed in a height-wise direction perpendicular to the direction ofmovement of the movable member 73 and is branched at its upper end intoa first pin intrusion guide groove 128 and a second pin intrusion guidegroove 129. These guide grooves 128, 129 are arcuate in shape inregister with the locus of rotational movement of the engagement pins 91to 93 provided at offset positions of the transfer gears 86, 88 and 90.That is, the pin intrusion guide grooves 128, 129 guide the intrusioninto the engagement groove 75 of the engagement pins 91 to 93 rotated inunison with the transfer gears 86, 88, 90.

When the transfer gears 86, 88 and 90 are run in rotation, the movablemember is intruded in the engagement groove 75 for the engagement pins91 to 93 provided on the transfer gears 86, 88 and 90, and is moved withrotation of one set of the transfer gears 86, 88 and 90 by being guidedby the movement guide shaft 69. As the transfer gears 86, 88 and 90 arerotated further, the one set of the engagement pins 91 to 93 engaged inthe engagement groove 75 is disengaged from the engagement groove 75.Next, the other set of the engagement pins 91 to 93 provided on theother set of the transfer gears 86, 88 and 90 are engaged in theengagement groove 75. By repetition of the engagement and disengagementof the engagement pins 91 to 93 in and out of the engagement groove 75,the movable members 73, 73 are moved over the extent of the transfergears 86, 88, 90.

That is, the engagement pins 91 to 93 are provided on the transfer gears86, 88, 90 so as to have the rotational phase difference in which theengagement and disengagement of the movable member 73 in and out of theengagement groove 75 is repeated with rotation of the sets of thetransfer gears 86, 88, 90 rotated in timed relation to each other. It isassumed that, when the engagement pins 91, 92, 93 are located on astraight line interconnecting the supporting shafts 118,120, 122supporting the transfer gears 86, 88, 90, the rotational angularposition of the engagement pins 91 to 93 is 0°. When the movable member73 is at the left-most position in FIG. 39, the third transfer gear 90is rotated to a position in which the third engagement pin 93 is at the0° rotational angular position.

If the counterclockwise rotational direction in FIGS. 39 to 44 of thetransfer gears 86, 88, 90 provided with the engagement pins 91 to 93 ispositive (+), the second transfer gear 88 is put in the initial positionshown in FIG. 39 in the state in which the second engagement pin 92 hasbeen rotated to a rotary position of (180°-Θ), while the first transfergear 86 is put in the state in which the first engagement pin 91 hasbeen rotated to a rotary position of (180°+Θ₁), wherein Θ₁, Θ₂, are setto 60°.

If the transfer driving gear 85 has been rotated in the negative (-)direction as indicated by arrow S₁ in FIG. 39, the third transfer gear90 is rotated in the positive (+) direction indicated by arrow S₄ inFIG. 40. By the rotation through 180° of the third transfer gear 90 inthe positive (+) direction, the movable member 73 is moved towards rightrear in FIG. 40 a distance substantially equal to the diameter of thethird transfer gear 90. The second transfer gear 88 is rotated in thepositive (+) direction as indicated by arrow S₃ in FIG. 41, and reachesa rotational position in which it has been rotated through (360°-Θ₂) or-60°.

When the third transfer gear 90 reaches a position in which it has beenrotated through 210°, the third engagement pin 93 is disengaged from theengagement groove 75 in the movable member 73 via a second pin intrusionguide groove 129 positioned at the left forward side in FIG. 41. Thesecond transfer gear 88 is rotated at this time to a position in whichthe second engagement pin 92 is intruded via the first pin intrusionguide groove 128 into the engagement groove 75.

When the third transfer gear 90 is rotated to a position in which it hasbeen rotated through 420° (one complete revolution and 60°) in thepositive (+) direction, the second transfer gear 88 reaches a positionin which it is rotated through 180°, while the movable member 73 isfurther moved towards right rear in FIG. 42 a distance substantiallyequal to the diameter of the second transfer gear 88. The first transfergear 86 is rotated at this time in the positive (+) direction asindicated by arrow S₂ in FIG. 42 to a position in which it has beenrotated through (360°-Θ₁) or -60°.

When the third transfer gear 90 is rotated to a position in which it hasbeen rotated through 450° (one full revolution and 90°), the secondengagement pin 92 formed on the second transfer gear 88 is put at aposition in which the second engagement pin 92 provided on the secondtransfer gear 88 is disengaged from the engagement groove 75 via thesecond pin intrusion guide groove 129, as shown in FIG. 43. The firsttransfer gear 86 is rotated to a position in which the first engagementpin 91 is intruded via the first pin intrusion guide groove 128 into theengagement groove 75.

When the third transfer gear 90 is rotated to a position in which it hasbeen rotated through 660° (one complete revolution and 300°) in thepositive (+) direction, the first transfer gear 86 reaches a position inwhich it is rotated through 180°, while the movable member 73 is furthermoved towards right rear in FIG. 44 a distance substantially equal tothe diameter of the first transfer gear 86 and reaches its rearmostposition. The first transfer gear 86 is rotated in the positive (+)direction as indicated by arrow S₂ in FIG. 44 to a position in which ithas been rotated through 180°.

If the transfer driving gear 85 has been rotated in the positive (+)direction as indicated by arrow T₁ in FIG. 39, the first to thirdtransfer gears 86, 88, 90 are rotated as indicated by arrows T₂, T₃ andT₄ in FIGS. 40 to 44, with the movable member 73 being moved towardsleft forward side from the right rear side in FIGS. 40 to 44.

As described above, the movable members 73, 73 are reciprocated insynchronism with each other by being guided along a pair of movementguide shafts 69, 69 depending on the rotational driving direction of thedriving motor for disc cartridge transfer 80.

On an inner lateral side of each movable member 73, 73 opposite to itslateral side carrying the engagement groove 75 is mounted the levermounting plate 98 engaged with a portion of the disc cartridge 320 or321 and constituting a cartridge holding mechanism holding the disccartridge 320 or 321. The lever mounting plate 98 is L-shaped incross-section and has its L-shaped arm secured to the inner lateral sideof each movable member 73 by set screws 116, 116, as shown in FIG. 22.

The set of the positioning lever 99 and the engagement lever 100 ismounted on a lever attachment plate 98 provided on each of the left andright sides in order to make up a holding mechanism for the disccartridge 320 or 321. The second recording medium transfer mechanism isconstituted by mounting the positioning lever 99 and the engagementlever 100 making up the cartridge holding mechanism on the leverattachment plate 98 for movement in unison with the movable member 73.

The positioning lever 99 is rotatably supported on the movable plate 98via a support shaft 109 and has on its one end an upwardly directedpositioning pin 110. The positioning lever 99 carries on its oppositeend an engagement pin 113 engaged in a groove 111 for engagement by theengagement lever 100. The engagement lever 100 carries on its oppositeend a pawl-shaped engagement portion 115 adapted for being engaged inengagement recesses 312, 312 formed on both sides of the disc cartridge320 or 321.

The engagement portions 115, 115 formed on left and right engagementlevers 100, 100 are engaged with the rotation of the engagement levers100, 100 in both engagement recesses 312, 312 on both lateral sides ofthe disc cartridge 320 or 321 facing the disc driving unit 8 for holdingthe disc cartridge 320 or 321.

The positioning pins 110, 110 provided on the left and right positioninglevers 99, 99 are selectively engaged in one of the first and secondengagement grooves 77, 78 formed on the lower surfaces of guide rails70, 70 in parallel with each other. When the positioning pins 110, 110are engaged in the first engagement grooves 77, 77 formed on the opposeinner sides of the guide rails 70, 70, the engagement levers 100, 100are rotated in the direction of being engaged in the engagement recesses312, 312 of the disc cartridge 320 or 321 or in the direction ofapproaching engagement portions 115, 115 towards each other. When thepositioning pins 110, 110 are engaged in second engagement grooves 78,78 formed on the outer sides of the guide rails 70, 70, the engagementlevers 100, 100 have been rotated to a position in which the engagementlevers are disengaged from the engagement recesses 312, 312 of the disccartridge 320 or 321, with the engagement portions 115, 115 beingseparated away from each other, as shown in FIG. 31. Further rotation ofthe engagement levers 100, 100 is prohibited by retention lugs 114, 114formed upright on opposite sides of the engagement levers 100, 100 beingcaused to bear against the opening end of the aperture 11e formed in thefront surface of the magazine main member 11a, as shown in FIG. 31.

A pair of operating levers 96, 96 for controlling the rotation of thepositioning lever 99 constituting the holding mechanism for the disccartridge 320 or 321 is mounted facing the opened front surface of thehousing 8a which is the forward end of each of the first and secondengagement grooves 77, 78, as shown in FIGS. 22 and 29. Each of theoperating levers 96, 96 is L-shaped and has its one end protruded intothe inside of the front surface of the housing 8a, while having thedistal end of its opposite side rotatably mounted via support shafts104, 104 set upright on a top plate 126 for facing the opened front endof the second engagement groove 78. The opposite end of each operatinglever 96 facing the first and second engagement grooves 77, 78 is arotating portion 106 for rotating the positioning lever 99. The distalend face of the rotating portion 106 is designed as a pin abutmentportion 107 abutted by a positioning pin 110 set upright on thepositioning lever 99. In the vicinity of the portion of the operatinglever 96 supported by a support shaft 104 is mounted a rotating member105 for rotating the positioning lever 99 in a depending manner, asshown in FIG. 22.

Each operating lever 96, 96 is rotationally biased by tension springs97, 97 mounted between spring retention pins 103, 103 set on one end ofthe lever 96, 96 and spring retainers 108, 108 at the mid portion of theforward side of the top plate 126 in a direction in which pin abutmentportions 107, 107 at the distal ends of the rotating portions 106, 106are located in the initial position of facing the opening ends of thesecond engagement grooves 78, 78. That is, each operating lever 96, 96is rotationally biased by the tension springs 97, 97 at all times so asto be restored to their initial position when the operating levers arerotated about the pivot shafts 104, 104 as the center of rotation andsubsequently freed of the rotational pressure.

At a mid position on the front end of the top plate 126 is arranged asolenoid plunger 94 adapted for rotating the operating levers 96, 96against the bias of the tension springs 97, 97. This solenoid plunger 94is mounted on the top plate 126 with its driving shaft 101 protrudedinto the inside of the housing 8a. The driving shaft 101 is engaged byone ends of a pair of rotating levers 95, 95 rotatably supported bysupport shafts 102, 102 set on the top plate 126, as shown in FIG. 29.The opposite ends of the rotating levers 95, 95 face spring retentionpins 103, 103 set on one ends of the operating levers 96, 96.

When the solenoid plunger 94 is driven in operation, the driving shaft101 is moved in the direction indicated by arrow P in FIG. 31 forrotating the rotating levers 95, 95 in a direction in which the rearends of the levers 95, 95 are moved towards rear or towards the insideof the housing 8a. When the rotating levers 95, 95 are rotated by thesolenoid plunger 94, the spring retention pins 103, 103 are thrust bythe opposite ends of the rotating levers 95, 95, whereby the operatinglevers 96, 96 are rotated in a direction indicated by arrow Q in FIG. 31against the bias of the tension springs 97, 97. By rotation of theoperating lever 96, 96 in the direction indicated by arrow Q in FIG. 31,the pin abutment portions 107, 107 at the distal ends of the rotatingportions 106, 106 are moved to a position which outwardly clears theposition facing the initial position of facing the opening ends of thesecond engagement grooves 78, 78, away from the initial position inwhich the pin abutment portions face the opening ends of the secondengagement grooves 78, 78.

When attachment plates 98, 98 attached to the movable members 75, 75 formovement in unison therewith are moved towards the front side of thehousing 8a and the positioning pins 110, 110 set on one ends of thepositioning levers 99, 99 mounted in position via these attachmentplates 98, 98 are disengaged from the first and second engagementgrooves 77, 78, the operating levers 96, 96, rotated by the rotatinglevers 95, 95 rotated in turn by the solenoid plunger 94, causesrotation of the positioning levers 99,99 by the rotating members 105,105, or thrusts the positioning pins 110, 110 by the rotating portions106, 106 for rotating the positioning levers 99, 99. That is, theoperating levers 96, 96 causes rotation of the positioning levers 99, 99for rotating the engagement levers 100, 100 for engaging or disengagingthe engagement portions 115, 115 provided on the engagement levers 100,1200 in or out of engagement recesses 312, 312 formed in the disccartridge 320 or 321.

If, when the solenoid plunger 94 rotating the operating levers 96, 96via the rotating levers 95, 95 is in an inoperative state, and thepositioning pins 110, 110 are engaged in the first and second engagementgrooves 77, 78, the attachment plates 98, 98 are moved in unison withthe movable members 75, 75 towards the front side as indicated by arrowL in FIG. 30, and the positioning pins 110, 110 are disengaged from thefront opening ends of the second engagement grooves 78, 78, thesepositioning pins 110, 110 are caused to bear against the pin abutmentportions 107, 107 at the distal ends of the rotating portions 106, 106for causing these rotating portions 106, 106 to clear outward in adirection opposite to arrow M in FIG. 30.

By such movement of the positioning pins 110, 110, the engagement levers100, 100 are rotated in a direction opposite to that indicated by arrowN in FIG. 30 for approaching the engagement portions 115, 115 at thedistal ends thereof towards each other. Thus the engagement portions115, 115 are intruded via the cut-outs 44, 44 into the housing section39 in the magazine for the disc cartridge 11 into engagement with theengagement recesses 312, 312 in the disc cartridge 320 or 321 facing thedisc driving unit 8.

The engagement lever 100 is caused at this time to bear against theengagement member 45 of the magazine for the disc cartridge 11 facingthe disc driving unit 8 for rotating and receding the engagement member45 from the housing 39 against the bias of the thrusting piece 50 out ofengagement with the engagement recesses 312, 312 of the disc cartridge320 or 321 housed within the housing section 39.

That is, the operating levers 96, 96 cause the movement of thepositioning pins 110, 110 provided on the positioning levers 99, 99 viathe rotating portions 106, 106, and are rotationally biased at all timesto their initial positions by the tension springs 97, 97 forrotationally biasing the engagement lever 100 in a direction in whichthe engagement portions 115, 115 are engaged in the engagement recesses312 formed in the disc cartridge 320 or 321 housed within the housingsection 39.

On the other hand, if the solenoid plunger 94 is driven in operation forrotating the operating levers 96, 96 in a direction of arrow Q in FIG.31 against the bias of the tension springs 97, 97, the positioning pins110, 110 cause rotation of the positioning levers 99, 99 intoregistration with the front opening ends of the second engagementgrooves 78, 78 via the rotating members 105, 105. By such rotation ofthe positioning levers 99, 99, the engagement levers 100, 100 arerotated as indicated in a direction of displacing the engagementportions 115, 115 away from each other as indicated by arrow R in FIG.31, for disengaging the engagement portions 115, 115 away from theengagement recesses 312, 312 of the disc cartridge 320 or 321.

If, as a result of rotation of the engagement levers 100, 100 via theoperating levers 96, 96 and the positioning levers 99, 99, caused by thedriving by the solenoid plunger 94, the engagement portions 115, 115 aredisengaged from the engagement recesses 312, 312 of the disc cartridge320 or 321, and the movable members 73, 73 are moved towards the insideof the housing section 39 in a direction opposite to that indicated byarrow L in FIG. 31, the positioning pins 110, 110 are progressivelyengaged into the second engagement grooves 78, 78 via the front endapertures thereof.

If, when the respective engagement levers 100, 100 have been rotated toa position in which the engagement portions 115, 115 are engaged in theengagement recesses 312, 312 in the disc cartridge 320 or 321, themovable members 73, 73 having mounted thereon the attachment plates 98,98 are moved by being guided by the movement guide shaft 69, the disccartridge 320 or 321 is moved on the wires 67, 67 in unison with themovable members 73, 73. When the respective movable members 73, 73 reachthe rearmost position of the housing section 39 indicated in FIG. 29,the disc cartridge 320 or 321, moved in unison with the respectivemovable members 73, 73, reach a position of facing the cartridge loadingunit on the attachment plate 59 for the recording/reproducing unit. Theattachment plate 59 is raised towards the disc cartridge 320 or 321transferred to a position facing the cartridge loading unit, whereby thedisc cartridge 320 or 321 is loaded on the cartridge loading unit on theattachment plate for the recording/reproducing unit 59.

When the disc cartridge 320 or 321 is transferred on the wires 67, 67towards rear, the shutter member 306 or 317, mounted on the disccartridge 320 or 321, is caused to bear against the shutter openingmember which then prohibits the movement of the shutter members, so thatthe shutter member is moved relative to the cartridge main member 305 or316 as far as the position of opening the aperture of the shuttermember. On the other hand, when the disc cartridge 320 or 321 istransferred forward on the wires 67, 67, the shutter member 306 or 317,placed at the aperture opening position, is prohibited from movement bya shutter closure member, not shown, being engaged in an engagementopening 308 formed in the shutter member 306 or 317. Thus the shuttermember 306 or 317 is moved relative to the cartridge main member 305 or316 as far as the aperture opening position.

The disc driving unit 8 has a lift gear 153 which not only transfers thedisc cartridge but also lifts the attachment plate 59 by rotation of alift driving gear 152, as shown in FIGS. 22 and 23. The lift gear 153meshes with lift driving gear 152 mounted on a transfer driving shaft 84rotated by a driving motor 80 controlling the vertical movement of theattachment plate 59 and lifts the attachment plate 59 by rotation of thelift driving gear 152. The lift gear 153 is rotatably supported via asupport shaft 154 on the bottom plate 58 so as to mesh with a rack gear178 provided on the slide plate 167, as shown in FIG. 35.

The driving gear 152 for rotationally driving the lift gear 153 has agear portion 179 and an arcuate lock portion 180 devoid of gears, asshown in FIGS. 27 to 47. The lock portion 180 is arcuate in profile,with the center of the arc coincident with a center shaft of the liftdriving gear 152. The lock part 180 has a height corresponding to a midheight of the gear portion 179.

The lift gear 153 rotated by the lift driving gear 152 has aninterrupted gearing 153a only on one of its major surfaces, with theinterrupt gearing 153a having a gear portion 183 over a pre-set angularextent, as shown in FIGS. 45 and 46. A gear-free portion 184, formed inthe interrupted gearing 153a, is arcuate in profile, centered about thecenter shaft of the lift gear 153, and has a height lower than thebottom of the valley of the gear portion 184. The lift gear 153 isarranged for engaging the interrupted gearing 153a with a rack gear 178of the slide plate 167, as shown in FIG. 27.

The opposite major surface of the lift gear 153 is formed with a drivetransmitting gear 153b meshing with the lift driving gear 152, as shownin FIGS. 46 and 47. The drive force transmitting gear 153b is made up ofa plurality of reentrant lock portions 182, a plurality of gear portions181 and an initial-position gear portion 192 formed intermediate betweenthese reentrant lock portions. Each lock portion 182 formed in the drivetransmitting gear 153b is designed to have a reentrant surface havingthe same radius of curvature as the lock portion 180 of the lift drivinggear 152. Each gear portion 181 formed in the drive transmitting gear153b has the number of teeth coincident with the number of teeth of thegear portion 179 of the lift driving gear 152. Meanwhile, theinitial-position gear portion 192 is not engaged with the gear portion179 of the lift driving gear 152, so that there is no need for theinitial-position gear portion 192 to have the number of teeth coincidentwith that of the gear portion 170 of the lift driving gear 179.

When the movable members 73, 73 are at foremost position towards thehousing section 39 shown in FIG. 30, the lift driving gear 152 has itsgear portion 179 engaged with the initial-position gear portion 192 orits vicinity of the driving transmitting gear 153b of the lift gear 153.The lift gear 153 is positioned at this time so that the gear-freeportion 184 of the interrupted gearing 153a faces the rack gear 178. Theslide plate 167 is positioned forwardly, that is towards the housingsection, under the bias of the tension spring 177. If the disc cartridgetransferring driving motor 80 is rotationally driven in the positivedirection for rotationally driving the transfer driving shaft 84, themovable members 73, 73 are moved towards rear as indicated by arrow L inFIG. 30, at the same time as the lift gear 153 is rotated via the gearportion 179 of the lift driving gear 152.

The rotation of the lift gear 153 by the lift driving gear 152 is by theplural gear portions 181 and the plural lock portions 182 of the drivetransmitting gear 153b. As long as the movable members 73, 73 are movedtowards rear away from the housing section 39, the driving force cannotbe transmitted to the slide plate 167 because the gear-free portion 184in the interrupted gearing 153a then continues to face the rack gear 178despite rotation of the lift gear 153.

When the movable members 73, 73 reach the rearmost position, the liftdriving gear 152 causes further rotation of the lift gear 153 via thedrive transmitting fear 153 for engaging the gear portion 183 of theinterrupted gearing 153a with the rack gear 178. By the gear portion 183meshing with the rack gear 178, the slide plate 167 is moved towardsrear for lifting the attachment plate for the recording/reproducing unit59. The disc cartridge 320 or 321, transferred towards rear in unisonwith the movable members 73, 73, is loaded at this time on the cartridgeloading unit on the attachment plate for the recording/reproducing unit59. On termination of movement of the slide plate 167 towards rear, thedrive motor 80 is halted, while the lift drive gear 152 is halted withthe lock portion 180 being engaged with the reentrant lock portion 182of the drive transmitting gear 153b, as shown in FIG. 28.

Since the drive motor 80 is rotationally driven until termination ofrearward movement of the slide plate 167, it may be feared that furtherrotation may be produced after the movable members 73, 73 have beenmoved to the rearmost position by the first transfer gears 86, 86.However, since the first engagement pins 91, 91 are disengaged at thistime from the movable members 73, 73 via the second pin intrusion guidegrooves 129, 129 at the forward sides of the movable members 73, 73, themovement of the movable members 73, 73 continues to be halted. When thedriving motor 80 has started to be rotationally driven in the reversedirection, the first engagement pins 91, 91 are again intruded into theengagement grooves 75, 75 via the second pin intrusion guide grooves129, 129 at the forward sides of the movable members 73, 73 in order topermit movement of the movable members 73, 73.

If, with the slide plate 167 being moved towards rear as describedabove, the driving motor 80 is driven in reverse, the lift gear 153 isrun in rotation. The slide plate 1678 is first restored to the forwardposition and the attachment plate for the recording/reproducing unit 59is moved towards below. Subsequently, the movable members 73, 73 aremoved forwards. When the movable members 73, 73 reach the foremostposition towards the housing section 39, the driving motor 80 is halted.

The lift mechanism for moving the disc driving units 8, 8 along thevertical direction, which corresponds to the stacking direction of thedisc cartridges 320 or 321 housed within the housing section 39, is nowexplained. The lift mechanism has a lift block 9 constituting a portionof the disc driving units 8, 8, as shown in FIGS. 48 to 53. The liftblock 9 has a bottom plate 9a and a pair of side plates 9b, 9b formedupright on opposite sides of the bottom plate 9a, as shown in FIG. 49.The lift block is supported by the support pillar 7 via a tubularbearing 146 mounted at the center of the bottom plate 9a so that thelift block is moved vertically by being guided by the support pillar 7.The support pillar 7 not only plays the part of a support for the liftblock but also plays the part of a guide for guiding the lift movementof the lift block 9.

The disc driving units 8, 8 are arranged on the lift block 9 with thepilar 7 in-between. The disc driving units 8, 8 are arranged on thebottom plate 9a of the lift block 9 so that the disc entry/exit openingsides thereof face the outer sides opposite to the sides facing thepillar 7.

The lift block 9 is arranged so that opposite sidewall sections 9b, 9bthereof run parallel to a pair of support plates 16, 16. The lift block9 is supported by a lift guide shaft 145 set upright on the main chassis13 parallel to the pillar 7 being introduced into a through-hole formedin the bottom plate 9a, as shown in FIGS. 48 and 49. Thus the lift blockis prohibited from rotation about its own axis. The upper ends of thepillar 7 and the lift guide shaft 145 are supported by a connectingplate 16a mounted on the upper ends of the support plates 16, 16.

A driving motor 135 for lifting the lift block 9 along the pillar 7 ismounted via a motor attachment plate 138 mounted on the support plate 16so that its driving shaft is parallel to the main chassis 13. A wormgear 136 for transmitting the driving force is mounted on a drivingshaft of the driving motor 135. The worm gear 136 meshes with a wormwheel 139 supported for rotation on a motor attachment plate 138 via asupport shaft 137. The support shaft 137 supporting the worm wheel 139carries a worm gear 140 arranged below the worm wheel 139. The worm gear140 has two strings of gears.

The worm gear 140 meshes with a pair of worm wheels 10, 10 rotatablymounted on the support plate 16 via support shafts 131, 131. These wormwheels 10, 10 are arranged on both sides of the worm gear 140. Thus theworm wheels 10, 10 are positioned with the major surfaces thereof lyingon the same plane.

On the worm wheels 10, 10 are mounted engagement pins 133, 133 as pairedengagement members via identically shaped connecting plates 132, 132.These engagement pins 133, 133 are protuberantly formed towards the liftblock 9, that is towards the pillar 7, so that the engagement pins runparallel to each other. The engagement pins 133, 133 are at the sameheight by adjusting the meshing position of the worm wheels 10, 10 withthe worm gear 140. Since the worm gear 140 has two strings of gears, theposition of the crests and valleys of the two gear strings arecoincident on both sides of the central axis. Thus the engagement pins133, 133 engaged with the two gear strings of the worm gear 140 may becoincident as to the axial engagement height of the worm gear 140.

The engagement pins 133, 133 are engaged in a pair of engagement grooves134, 134 formed in one of the side plates 9b of the lift block 9. Theseengagement grooves 134, 134 are symmetrically formed in theleft-and-right direction as elongated holes each having the horizontaldirection perpendicular to the lift direction of the lift block 9 as thelong diameter, with the support pillar 7 as the center.

A spur gear 141 is mounted on the upper end of a support shaft 137carrying the worm wheel 139. A gear attachment plate 138a having thesame configuration as the motor attachment plate 138 mounted on thesupport plate 16 is mounted on the opposite side support plate 10. Thegear attachment plate 138a has the spur gear 141 and the rotatablesupport shaft 137 carrying the worm gear 140 at its upper end and at itslower end, respectively. The worm gear 140 has two gear strings whichare the same as those provided on the worm gear mounted on the motorattachment plate 138.

Similarly to the support plate 16, the opposite support plate 16 carriesa pair of rotatable worm wheels 10, 10 via support shafts 131. Theseworm wheels are engaged with the worm gear 140 from both sides. On theworm wheels 10, 10 are mounted a pair of engagement pins 133, 133 asengagement members via the identically shaped connecting plates 132,132. The engagement pins 133, 133 are mounted parallel to each other andprotuberantly formed towards the lift block 9, that is towards thepillar 7. In addition, the engagement pins 133, 133 are maintained atthe same height by adjusting the meshing positions of the worm wheels10, 10 with the worm gear 140. These engagement pins 133, 133 areengaged in a pair of engagement grooves 134, 134 formed in the oppositeside plate 9b of the lift block 9 as elongated openings each having thehorizontal direction extending at right angles to the lift direction ofthe lift block 9 as the long axis.

A timing belt 130 is placed between put gears 141, 141 mounted at theupper ends of supporting shafts 137, 137 mounted in turn on the motorattachment plate 138 and a gear attachment plate 138a respectivelymounted on a pair of supporting plates 16, 16. That is, the spur gears141, 141 are rotated in synchronism with each other at the same speedand in the same direction. The pairs of the engagement pins 133, 133positioned on both sides of the lift block 9 are maintained at the sameaxial height along the support pillar 7 by adjusting the rotationalposition of the spur gears 141, 141.

With the above-described lift mechanism, the worm wheels 10, 10 arerotated in the directions indicated by arrows U and V in FIG. 53 byoperation of the driving motor 135 whereby the lift block 9 is liftedalong the support pillar 7 in the vertical direction as indicated byarrow W in FIG. 53. Since the engagement pins 133, 133 are engaged atthis time in the engagement grooves 134, 134 provided in the lift block9 at the symmetrical position in the transverse direction with respectto the support pillar 7, the lift block 9 is moved in a translatorymovement in the vertical direction.

On the main chassis 13 is arranged a reset switch 190 for detecting thatthe lift block 9 and the disc driving units 8, 8 supported by the liftblock 9 are at the lower most position towards the main chassis 13. Thereset switch 190 may be a thrust type switch which is actuated by beingthrust by a portion of the lift block 9 when the lift block 9 reachesthe lower most position.

A position detection scale plate 142 is mounted in the vicinity of andin parallel with the support pillar 7. The position detection scaleplate 142 has plural detection holes 147 at an equal interval X alongthe direction of lift movement of the lift block 9 corresponding to theheight of the support pillar 7, as shown in FIGS. 54 and 55. On the liftblock 99 are mounted first and second photosensors 143, 144 making up aposition sensor. Optical sensors, such as photocouplers, each havingdetection units 148, 149, are employed as the photosensors 143, 144.These optical sensors are mounted in position so that, when thedetection unit 148 of the first optical sensor 143 is located at theupper edge of the detection hole 147, the detection unit 149 of thesecond optical sensor 144 is located slightly above the lower edge ofthe opposite detection hole 147. That is, the distance between thedetection units 148 and 149 along the height indicated by arrow Y inFIG. 54 is selected to be slightly shorter than the distance X betweenthe detection holes 147, 147 plus the height of one of the detectionholes 147.

The detection output of the optical sensors 143, 144 is high (H) or low(L) when the detection units 148, 149 are or are not facing thedetection holes 147, respectively. These detection outputs of theoptical sensors 143, 144 are supplied to a control circuit.

If the detect outputs of the optical sensors 143, 144 are denoted 143aand 144a, respectively, the detection outputs 143a and 144a when thelift block 9 is moved along the support pillar 7 become H level and lowlevel outputs, which are periodically issued with movement of the liftblock 9, as shown in FIG. 56. At this time, the detection outputs of theoptical sensors 143, 144 are dephased relative to each other, as shownin FIG. 56, such that the detection outputs of the optical sensors 143,144 simultaneously become H level only during the short time interval Zin FIG. 56 when the detection units 148, 149 of the optical sensors 143,144 face the detection holes 147 simultaneously. Consequently, thedistance of movement of the lift block 9 may be detected by counting theevents of the detection outputs of the optical sensors 143 and 144becoming H level simultaneously. That is, by detecting the distance bywhich the lift block 9 is moved upwards after actuation of the resetswitch 190 by movement of the lift block 9 having been moved to thelowermost position towards the main chassis 13, it becomes possible todetect the position of the lift block 9 and that of the disc drivingunits 8, 8 moved in unison therewith. On the other hand, by halting thelift block 9 at the position for which the detection outputs of theoptical sensors 143, 144 become H level simultaneously, the lift block 9can be halted at equally spaced apart plural stop positions along theheight of the support pillar 7.

After the detection operation by the photosensors 143, 144 is reset bythe reset switch 190, the control circuit supplied with the detectionoutputs of the photosensors 143, 144 counts the events of the detectionoutputs of the photosensors 143, 144 going H simultaneously fordetecting the distance traversed by the lift block 9 for detecting theposition of the disc driving units 8, 8 moved along with the lift block9.

By vertically moving the disc driving units 8, 8 by the lift mechanismalong the height of the support pillar 7, it becomes possible for thedisc driving units 8, 8 to select one of the disc cartridges 320 or 321accommodated within the magazines for the disc cartridges 11, 11 facingthe disc driving units 8, 8. That is, by correctly halting the liftblock 9 at one of plural pre-set equally spaced apart positions, thedisc driving units 8, 8 may be correctly halted at the height positionin which the engagement levers 100, 100 are in registration with therespective engagement recesses 312, 312 of the disc cartridges 320, 321accommodated within the magazines for the disc cartridges 11, 11.

The reset switch 190 may be arranged at the uppermost position of theposition detection scale plate 142 so that, on detection that the liftblock 9 and the disc driving units 8, 8 reach the upper limit positionfor the lift mechanism, the detection operation by the optical sensors143, 144 is reset.

With the disc recording and/or reproducing apparatus having the discexchange function, according to the present embodiment, the informationsills, such as music signalman be recorded on or reproduced from pluraldiscs by accommodating a suitable number of the disc cartridges 320 or321 in the toroidally arranged plural magazines 11 on the turntable 15,selecting one or two of these disc cartridges 320 or 321 and bysequentially loading the selected disc cartridges on the disc drivingunits 8, 8.

The operation of selecting the disc cartridges 320 or 321 accommodatedin the magazines 11 and recording and/or reproducing information signal,such as music signals, on or from the discs accommodated within theseselected disc cartridges 320 or 321, is hereinafter explained.

The recording/reproducing operation by the disc recording and/orreproducing apparatus is initiated by supplying an operation controlsignal to the control circuit by an operating unit, not shown. First,the desired one of the disc cartridges 320 or 321 is selected from amonga number of disc cartridges 320 or 321 accommodated within the magazinesfor the disc cartridges 11 arranged toroidally on the turntable 15 bydesignating an M address which is an address number of from 1 to 8 foridentifying one of the magazines 11 on the turntable 15, and bydesignating a D address which is an address number of from 1 to 10 foridentifying the disc cartridges 320 or 321 in one of the magazines fordisc cartridges 11.

With the disc recording and/or reproducing apparatus of the embodimentillustrated, the turntable 15 is rotated by driving the driving motor 18adapted for rotationally driving the turntable 15 in accordance with theM address designating one of the plural magazines 11 on the turntable,while the disc driving units 8, 8 are lifted by driving the lift drivingmotor 135 by lifting the disc driving units 8, 8 in accordance with theD address designating one of the disc cartridges 320 or 321 accommodatedwithin the designated magazine 11. The driving control of the drivingmotor 18 for the turntable 15 and the driving motor 135 for moving thelift block 9 may also be effected simultaneously. When the turntable 15and the respective disc driving units 8, 8 are moved to the positionsdesignated by the M address and the D address, the disc driving units 8,8 are faced by the selected disc cartridge 320 or 321. At the respectivedisc driving units 8, 8, the movable blocks 73, 73 are spaced apart atthis time from the housing section 39 of the magazine 11, while theengagement pins 110, 110 are engaged with the second engagement grooves78, 78.

If, after the selection of the disc cartridge 320 or 321 has come to anend, the driving operation by the driving motor 80 for cartridgetransfer is started, and the movable members 73, 73 are moved to theforemost position close to the housing section 39 of the magazine 11,the engagement levers 100, 100 are engaged with the engagement recesses312, 312 of the disc cartridge 320 or 321 housed within the housingsection 39. If the driving motor 80 for transfer of the disc cartridgeis rotated in the positive direction, the disc cartridge 320 or 321,engaged with the engagement levers 100, 100, is transferred into theinside of one of the disc driving unit 8 and loaded on the cartridgeloading unit on the attachment plate for the recording/reproducing unit59.

The M address for designating the magazine 11 on the turntable 15 andthe D address for designating the disc cartridge 320 or 321 accommodatedwithin each magazine 11 may be individually designated for each of thedisc driving units 8, 8. After the loading of the disc cartridge 320 or321 on one of the disc driving units 8 has come to a close, the disccartridge 320 or 321 is selected and loaded on the other disc drivingunit 8.

After the disc cartridge 320 or 321 is loaded on the cartridge loadingunit on the attachment substrate for the recording/reproducing unit 59of each disc driving unit 8, 8, the information signals may be recordedon or reproduced from the disc accommodated in the disc cartridge. Onthe other hand, the disc cartridge 320 or 321 may be expelled, selectedor loaded for one of the disc driving unit 8 while the informationsignals are being recorded on or reproduced from the other disc drivingunit 8.

The disc cartridge 320 or 321 loaded on the disc driving units 8, 8 maybe restored to the original position in the original magazine 11 inaccordance with the designated M address and the designated address.That is, after the rotational position of the turntable 15 and theheight position of the disc driving units 8, 8 have been restored inaccordance with the M address and the D address to the originalpositions corresponding to loading of the disc cartridge 320 or 321, thedriving motor 80 for the disc cartridge transfer is rotationally drivenin the opposite direction to that for loading for restoring the loadeddisc cartridge 320 or 321 to the original position within the magazine11. The solenoid plunger 94 is driven at this time for disengaging theengagement levers 100, 100 from the engagement recesses 312, 312 in thedisc cartridge 320 or 321, after which the movable blocks 73, 73 aremoved towards rear away from the housing section 39. The engagementrecesses 312 of the disc cartridge 320 or 321, restored into themagazine for the disc cartridge 11, are engaged by the engagementmembers 45 provided in the housing section 39.

With the disc driving and/or reproducing apparatus, it is possible toarrange the disc driving unit 8 on the turntable 15 and to provide themagazines for the disc cartridges 11 on the lift block 9 arranged on themain chassis 13. The disc driving unit 8 is rotated by the riving gear26 via the ring gear 28, and is selectively faced by one of the disccartridges 320 or 321 housed within the magazine 11 when the engagementlug 27 of the driving gear 26 is engaged with one of the engagementrecesses 29a to 29h of the ring gear 28.

The lift mechanism may also be employed as a lift for lifting themagazines for the disc cartridges 11.

What is claimed is:
 1. A disc magazine comprising:a casing substantiallyin the form of a parallelepiped for housing a plurality of disccartridges so that the major surfaces thereof run parallel to oneanother, said casing having apertures on opposite lateral sides thereoffor taking out and housing a plurality of the disc cartridges, holdingmeans for engaging with recesses in the disc cartridges housed withinsaid casing via one of the apertures in said casing for holding saiddisc cartridges in said casing, and stop means in the opposite aperturein the casing for prohibiting the disc cartridges from retreating fromthe casing via said opposite aperture.
 2. The disc magazine as claimedin claim 1 wherein said holding means comprises a plurality ofengagement members engaged with the recesses in the disc cartridgeshoused within said casing and a plurality of biasing members for biasingthe engagement members in a direction of being engaged with the recessesin the disc cartridges.
 3. The disc magazine as claimed in claim 2wherein said stop means comprises a stop member movable between aposition of being protruded at said opposite aperture and a position ofbeing receded from said opposite aperture.
 4. The disc magazine asclaimed in claim 1 wherein:said holding means comprises a plurality ofengagement members engaged with the recesses in the disc cartridgeshoused within said casing and a plurality of biasing members for biasingthe engagement members in a direction of being engaged with the recessesin the disc cartridges; and said stop means comprises a stop membermovable between a position of being protruded at said opposite apertureand a position of being receded from said opposite aperture.
 5. The discmagazine as claimed in claim 1 wherein:said holding means comprises aplurality of engagement members movable between a position of intrudingor receding a plurality of engagement portions into or out of thecasing; wherein the plurality of engagement members are engaged with therecesses in the disc cartridges housed within said casing and aplurality of biasing members for biasing the engagement members in adirection of being engaged with the recesses in the disc cartridges; andsaid stop means comprises a stop member movable between a position ofbeing protruded at said opposite aperture and a position of beingreceded from said opposite aperture.